When choosing a diamond, the first decision to bemade is what shape you prefer. Diamonds comein a wide range of shapes, with the most popularbeing a round brilliant cut – which most people willrecognise as the classic shape for a solitaire stylering. Other common shapes include oval cut,emerald cut, pear cut, marquise cut, cushion cut,radiant cut, princess cut and trilliant or trillion cut,along with other more unusual shapes, each withtheir own unique qualities to suit different stylesand preferences.​

The carat of a diamond is the measurement used to determine its weight, with 200 milligrams making up 1 carat. This contributes to the size of the stone, although not all stones of the same carat weight have the same dimensions, as some appear larger or smaller from the top, while others can be larger or smaller from the side view. This is generally most noticeable in fancy shape stones such as oval and pear cuts, while round cut diamonds tend to follow more standard rules of proportion.​

All else being equal, diamond price increases with carat weight, because larger diamonds are rarer and more desirable. However, two diamonds of equal carat weight can have very different values depending on the different quality factors that they present.​

The cut of a diamond is not to be confused with its shape. Cut refers here to the quality of how it’s been cut, which is important in ensuring the maximum return of light back to the viewer’s eye.  This return of light is the factor that fuels a diamond’s fire, sparkle and brilliance. Precise workmanship is required to cut a diamond so that its proportions, symmetry, and polish maximise its beauty. Cut grades are unique to round brilliant cut diamonds only, and do not apply to any other shape. The quality of cut is crucial to the diamond’s value, and at NMJ we work only with excellent cut round diamonds.​

​​For fancy shape diamonds, which is the term applied to all other shapes outside of round, it is the polish and symmetry grades which determine the quality of the cut of the stone. A high quality fancy cut diamond will present very good to excellent polish and symmetry, whereas a round diamond should have excellent grading for both categories.​

Colour refers to the natural body colour of a diamond and not to the reflection of spectral colours that flash when a diamond moves. Most diamonds naturally exhibit slight hints of yellow, brown, or grey, and so the less colour a diamond exhibits, the higher it’s value due to the rarity of colourless material. Colour quality is graded via an alphabetical system, ranging from D (colourless) to Z (light yellow). Each letter grade represents a range of colour and is a measure of how noticeable that colour is. To guarantee a high quality, bright white diamond NMJ source only from the colourless quality range, which are D, E and F grades.​

​​FLUORESCENCE​

The fluorescence of a diamond is an unfamiliar factor to many people, but it’s important to be aware of the fluorescent grading system when choosing a diamond. A stone that exhibits fluorescence will glow blue under ultraviolet light, which ranges from a faint, dull blue light through to a vivid, bright blue luminescence. The less fluorescence a stone has, the higher it’s value, and at NMJ we use only stones which have no fluorescence.​

The clarity of a diamond refers to the presence of inclusions within the stone. Practically all diamonds contain naturally occurring internal inclusions. These are generally either foreign materials, such as carbon or other minerals which were trapped inside the diamond as it has grown around them, or clear inclusions such as fractures and tiny imperfections in the structure of the diamond. The size, nature, location and amount of inclusions determine a diamond’s clarity grade and affect its value. The diamonds that we source at NMJ are strictly SI1 clarity and above, and we encourage prioritising a stone with no eye-visible inclusions to guarantee the best sparkle and fire. To ensure the best diamond we recommend a VS2 or higher clarity quality.​